amd64/isel: fix addressing index shift being possibly too large to encode (duh)

2 files changed, 2 insertions, 1 deletions

diff --git a/amd64/emit.c b/amd64/emit.c
index 14b679f..5cabd09 100644
--- a/amd64/emit.c
+++ b/amd64/emit.c
@@ -132,6 +132,7 @@ mkmemoper(union ref r)
       const struct addr *addr = &addrht[r.i];
       struct oper mem;
 
+      assert(addr->shift <= 3);
       if (addr->base.t == RTMP && ioper(addr->base.i).t == OMEM) {
          mem = ioper(addr->base.i);
          if (addr->index.bits) addmemoper(&mem, mkregoper(addr->index));
diff --git a/amd64/isel.c b/amd64/isel.c
index 9065ccf..3611670 100644
--- a/amd64/isel.c
+++ b/amd64/isel.c
@@ -214,9 +214,9 @@ ascale(struct addr *addr, union ref a, union ref b)
 {
    if (b.t != RICON) return 0;
    if (addr->index.bits) return 0;
+   if ((unsigned)b.i > 3) return 0;
    if (a.t == RREG) {
    Scaled:
-      if ((unsigned)b.i > 3) return 0;
       addr->index = a;
       addr->shift = b.i;
       return 1;